Deployment of Stents within Bifurcated Vessels

ABSTRACT

Systems and methods for deploying stents within bifurcated vessels in a true pantaloons configuration (Kamat technique) are disclosed. A device including a balloon catheter and a stent surrounding the catheter is inserted into a bifurcated blood vessel. The catheter includes a first lumen configured to accept a first guide wire, which exits the device at a distal end. The device is advanced within a main branch using the first guide wire until it reaches the carina, thus causing the second guide wire to enter a second side branch. The second wire exits the device at a tapered edge of the catheter from under the stent. The stent may then be deployed within the main branch. The stent may then be splayed across the carina with kissing balloons and the procedure may be completed with the kissing balloon deployment of two stents accurately at the carina in each side branch.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. patent applicationSer. No. 14/072,042, which is titled “Deployment of Stents withBifurcated Vessels and was filed on Nov. 5, 2013, which is acontinuation of U.S. patent application Ser. No. 13/473,892, which istitled “Deployment of Stents with Bifurcated Vessels and was filed onMay 17, 2012, which claims the benefit of the filing date of U.S.Provisional Patent Application No. 61/528,968, which is titled “Systemsand Methods for Deploying Stents within Bifurcated Blood Vessels” andwas filed on Aug. 30, 2011, the disclosures of which are herebyincorporated by reference herein in their entirety.

TECHNICAL FIELD

This specification relates generally to systems and methods for stentdeployment, and, more particularly, to systems and methods for deployingstents within bifurcated vessels.

BACKGROUND

Bifurcation occurs when a vessel (or main branch) splits into twoseparate blood vessels (or side branches). Typically, the two sidebranches are smaller than the main branch. In the case of blood vessels,plaque buildup in the bifurcated region may cause stenosis or otherwisecompromise blood flow. These types of lesions may occur within the mainbranch as well as in the side branches.

Over the years, a few techniques have been developed to attempt to treatlesions at bifurcations. An example of a bifurcation stent deliverydevice is described in U.S. Patent Application Publication No.2005/0209673 (Shaked). Specifically, Shaked's device uses an additionallumen to accommodate a secondary guide wire that is inserted into a sidebranch at a bifurcation. The inventor hereof has recognized, however,that the exit point for the secondary guide wire occurs at the midpointof the device. As a result, the struts from the exit point may getincorrectly aligned, which may hinder the deployment of a side branchstent.

Another bifurcation device is disclosed in U.S. Pat. No. 7,686,845(Sequin). Sequin's device uses a self-expanding stent, which theinventor hereof has also recognized tends to be difficult to maneuverand deploy, especially if the plaque burden in the vessel is high.Moreover, the struts of Sequin's stent are subject to grabbing on toplaque during deployment, which may result in inaccurate placement ofthe stent, damage to the vessel, plaque shift, dissection, or evenplaque embolization.

SUMMARY

The currently existing limiting factors for bifurcation stenting can beovercome by novel techniques described herein, which: a) accuratelyidentify the location of the carina in two dimensional angiographicviews, b) accurately position the stents at the carina, c) accuratelydeploy the stents in relation to the carina, d) position wires in themain lumen and the side branches without going through stent struts, e)cover the entire area of the bifurcation so as to get a smooth luminaloutcome initially without plaque protruding within the lumen (e.g., 100%coverage of the area is particularly important to obtain theanti-restenosis benefit of drug eluting stents), f) avoid stent strutsfrom protruding within the lumen where blood flows—a problem associatedwith stent thrombosis, g) allow for reintervention in the future totreat new lesions distally or restenosis of the bifurcation withoutbeing hindered by the previously deployed bifurcation stents (e.g., theabsence of jailed side branches provides natural anatomic side branchaccess later), h) allows for completion of a bifurcation stentingprocedure with predictable, timely success without complications in thehands of competent operators with common and adequate skills, i) resultin low radiation and limited contrast use, j) avoid the need for bypasssurgery as the first option or as a complication of the procedure, k)use available (albeit off-label) stent technology to achieve successfulresults, and l) creates the possibility that industry can adapt thesechanges without the need to invent new stents, but instead bymodification of existing balloons and channels.

Systems and methods for accurately deploying stents within bifurcatedvessels are disclosed. In an illustrative, non-limiting embodiment, amethod may include inserting a device into a bifurcated vessel (i.e., acoronary or non-coronary blood vessel, a tracheobronchial tree, a venoussystem, a ureter, etc.), the device including a balloon catheter and astent, the stent surrounding at least a portion of the balloon catheter,the balloon catheter including a first lumen configured to accept afirst guide wire, the first guide wire exiting the device at a distalend of the balloon catheter, and the bifurcated vessel including a mainbranch, a first side branch, a second side branch, and a carina regionbetween the first and second side branches.

The method may also include advancing the device within the main branchof the bifurcated vessel over the previously placed first guide wireuntil the device reaches the carina region. The first guide wire may bemaneuvered into the first side branch and/or a second guide wire mayenter the second side branch. Also, the second guide wire may exit thedevice immediately beyond the distal edge of the stent that surroundsthe balloon catheter from under the stent. The distal edge of the stentmay be placed at or just ahead of the distal tapered edge of the balloon(e.g., the proximal edge of a distally located tapered portion of theballoon). As the stent approaches the carina of the bifurcation, thesecond wire may enter the second side branch, thereby physicallypositioning the distal edge of the stent at the carina.

The method may further include deploying the stent within the mainbranch of the bifurcated vessel by inflating the balloon when the stentis so positioned. In some cases, the diameter of the stent and balloonmay be sized for the main branch. The tapered portion of the balloon maybe in the first side branch such that it does not push the stent back ifthe stent is located sufficiently at or slightly ahead of the taperedshoulder. As the balloon is being deflated, the second wire that isunder the stent exterior to the balloon may be advanced forward into thesecond side branch. In this manner, each side branch receives a wire,and both these wires are located within the lumen of the stent of themain vessel. Subsequently, kissing balloons may be used to expand and/orsplay this stent to conform to the wider lumen at the bifurcation.

In some implementations, a bifurcation stent balloon device for accuratedeployment at the bifurcation may have been pre-assembled in vitro.Further, such a device may include any available drug coated stent aswell as non-drug coated, bare-metal stents (although it is recognizedthat the latter may result in a higher likelihood of stenosis). Themethod may also include reconfiguring the device prior to inserting thedevice into the bifurcated vessel. This may include, for example,sliding the stent off of the balloon catheter. The method may alsoinclude placing the second guide wire between an inner surface of thestent and an outer surface of the balloon catheter, and sliding thestent back onto the balloon catheter with the distal edge of the stentpositioned at the distal, tapered edge of the balloon catheter (e.g., asidentified by a distal balloon marker, or the like). In some cases, thestent may be crimped onto the balloon at its new distal forwardlocation. The crimping of the stent may be achieved, for example, byfirmly winding a #2 silk suture over the stent.

In other implementations, a novel balloon catheter may include a secondlumen, the second lumen configured to accept the second guide wire, aportion of the first guide wire exiting the device at the distal end ofthe balloon catheter in parallel with respect to a portion of the secondguide wire exiting the device at the tapered edge of the ballooncatheter. For example, an edge of the stent may be positioned at thetapered edge of the balloon catheter. As such, the first guide wire maybe configured to exit the first lumen at a center of the distal portionof the balloon catheter, and the second guide wire may be configured toexit the second lumen at a periphery of the balloon on the ballooncatheter.

As such, the second wire may be maneuvered and/or advanced into thesecond side branch as the stent approaches the bifurcation. It is notedthat the crossing profile of such a configuration may be suitable fornumerous applications. The second wire lumen may be placed under thestent and extend backwards to the hub of the balloon attached to theshaft or free from the shaft up to the stent. Alternatively, the secondlumen may be located only at the balloon under the stent. In the lattercase, the second wire may be pre-positioned into the second side branchwith due care taken that the two wires remain parallel and do not windaround the each other. If necessary, this parallel position of the wiresmay be accomplished, for instance, using a dual lumen introducer deviceor the like.

In various situations, deploying the stent within the main branch of thebifurcated vessel may include inflating the balloon catheter to deploythe stent while maintaining access to the first side branch of thebifurcated vessel via the first guide wire and/or to the second sidebranch of the bifurcation via the second guide wire. Moreover, deployingthe stent within the main branch of the bifurcated vessel may includeapplying a first kissing balloon technique to expand and/or splay thedistal end of the stent. The method may then include deploying anotherstent within the first side branch of the bifurcated vessel using thefirst guide wire and/or deploying another stent within the second sidebranch of the bifurcated vessel using the second guide wire.

In some cases, the stent may be sized appropriately for each side branchvessel. A kissing stent technique may be used with accurate placement ofthe stents using the visualized splayed first stent in the main branchand the visualized proximal edge of the stents in each side branch, soas to accurately deliver the stents at the carina. To avoid damage tothe vessels, high-pressure inflation of one stent (e.g., ˜12 atm) may beaccompanied with a lowering of the pressures in the other balloon (e.g.,˜3 atm). Thereafter, both balloons may be brought to the same mediumpressures (e.g., ˜6 atm), and then both may be deflated at the same timeso as to leave the carina in a central position. The two balloons may bepulled back into the main branch stent and inflated in a similar fashionto ensure that the splayed proximal stent and the two branch stents arepushed into the wall of the vessel, thus leaving behind a smooth truepantaloons bifurcation configuration.

In another illustrative, non-limiting embodiment, a method may includereceiving a premanufactured assembled device including a ballooncatheter and a stent, the stent surrounding at least a portion of theballoon catheter, the balloon catheter including a first lumen, thefirst lumen configured to accept a first guide wire. The method may alsoinclude placing the stent on the balloon catheter after adding a secondguide wire between an inner surface of the stent and an outer surface ofthe balloon catheter. The method may further include crimping the stentback onto the balloon catheter.

The method may also include advancing the balloon catheter within avessel using the first guide wire until the balloon catheter stops at acarina of a bifurcation due, at least in part, to the carina contactingthe second guide wire, and deploying the stent between a first sidebranch and a second side branch of the bifurcation. Then, the method mayinclude delivering a second stent to the first side branch of thebifurcation using the first guide wire and/or delivering a third stentto the second branch of the bifurcation using the second guide wire.

In yet another illustrative, non-limiting embodiment, a device mayinclude a balloon catheter including a first lumen and a second lumen,the first lumen configured to receive a first guide wire and the secondlumen configured to receive a second guide wire, the first lumen havinga first exit at a center of a distal end of the balloon catheter, andthe second lumen having a second exit at a shoulder of the ballooncatheter. The balloon catheter, upon being inflated, may have a conicalportion between the shoulder and the distal end.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, wherein:

FIG. 1 is a diagram of a bifurcated vessel.

FIGS. 2A-E are diagrams of dual-lumen balloon catheters according tosome embodiments.

FIG. 3 is a cross-sectional view of the balloon catheter according tosome embodiments.

FIGS. 4A-H are diagrams of bifurcation stent delivery devices accordingto some embodiments.

FIG. 5 is a flowchart of a bifurcation stent delivery techniqueaccording to some embodiments.

FIG. 6 is a diagram of a bifurcation stent delivery device introducedinto a main branch toward a bifurcation lesion according to someembodiments.

FIG. 7 is a diagram of the bifurcation stent delivery device positioninga stent at the carina of the bifurcation according to some embodiments.

FIG. 8 is a diagram of the bifurcation stent delivery device deployingthe stent at the carina according to some embodiments.

FIG. 9 is a diagram of the stent with the balloon removed and theexpanded stent accurately positioned across the carina according to someembodiments.

FIG. 10 is a diagram of kissing balloons used to splay the stent acrossthe carina according to some embodiments.

FIG. 11 is a diagram of the stent fully splayed across the carinaaccording to some embodiments.

FIGS. 12A and 12B are diagrams of three stents being positioned at thebifurcation according to some embodiments. FIG. 12B demonstrating thefinal results of the creation of a true pantaloons bifurcation stentingconfiguration.

FIGS. 13A and 13B are simplified diagrams of an open-cell and aclosed-cell stent according to some embodiments.

FIG. 13C is a diagram of a bifurcation stent delivery device employing asingle-lumen catheter, according to some embodiments. Here the secondwire is trapped under the stent by crimping the stent over it.

FIG. 14 is a flowchart of a bifurcation stent delivery device assemblyusing a single-lumen catheter with a closed-cell stent according to someembodiments.

FIG. 15 is a flowchart of a bifurcation stent delivery device assemblyusing a single-lumen catheter with an open-cell stent according to someembodiments.

FIGS. 16A-C are diagrams of alternative delivery devices according tosome embodiments.

FIGS. 17A-B illustrate a three-stent delivery device according to analternative embodiment.

While this specification provides several embodiments and illustrativedrawings, a person of ordinary skill in the art will recognize that thepresent specification is not limited only to the embodiments or drawingsdescribed. It should be understood that the drawings and detaileddescription are not intended to limit the specification to theparticular form disclosed, but, on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the claims. Also, any headings used herein are fororganizational purposes only and are not intended to limit the scope ofthe description. As used herein, the word “may” is meant to convey apermissive sense (i.e., meaning “having the potential to”), rather thana mandatory sense (i.e., meaning “must”). Similarly, the words“include,” “including,” and “includes” mean “including, but not limitedto.”

DETAILED DESCRIPTION

This specification discloses systems and methods for accuratelydeploying stents within bifurcated vessels. Examples of “bifurcatedvessels” include, but are not limited to, bifurcated blood vessels(coronary, carotid, iliac, or other blood vessels), tracheobronchialtrees, venous systems, ureters, etc. Although the embodiments discussedbelow occasionally refer to specific types of vessels (e.g., bloodvessels), it should be understood that these examples of intravascularstents are provided for sake of illustration only, and not by way oflimitation. Moreover, it should be noted that the various embodimentsillustrated in the figures and discussed below are not necessarily drawnto scale, but are instead presented with dimensions intended facilitatetheir understanding.

In various embodiments, the methods described herein include deploying astent at the main branch of a bifurcated vessel by positioning the stentaccurately at the carina of the bifurcation while maintaining access toone or more side branches, and then deploying one or more additionalstents in the side branches of the bifurcation. In some implementations,these methods may be performed by employing at least two distinct typesor groups of stent delivery devices. A first group of devices includes aballoon catheter manufactured with two or more lumens or channelsconfigured to accommodate two or more separate guide wires (i.e., adual-lumen catheter as shown in FIGS. 2A-D, or a triple-lumen catheter,as shown in FIG. 2E). The pre-manufactured models may include multipleballoons in some embodiments. A second group of devices includesalternatives to the pre-manufactured dual-lumen catheter. An existingsingle-lumen balloon catheter may be modified so that it is capable ofperforming the same or similar operations as the pre-manufacturedmodels. For example, a secondary guide wire may be placed between thestent and a single-lumen balloon catheter in an “off-label” procedure(e.g., FIG. 13C). Additionally or alternatively, a dual-balloonconfiguration with a single stent crimped over two balloons may bedesigned to help position the stent at the carina (e.g., FIG. 16A).Additionally or alternatively, a stent may be crimped over a combinationof a balloon catheter and a long tube catheter with an approximately0.014-inch wire lumen or the like to facilitate accurate delivery at thecarina while maintaining dual side branch access through the stent lumen(e.g., FIGS. 16B and 16C). These various devices, as well as theircorresponding manufacturing and delivery methods, are described in turnbelow.

Stent Delivery with Multi-Lumen Balloon Catheters

In some embodiments, stent delivery devices may employ balloon cathetersmanufactured with two or more lumens (the first group or type of devicesdescribed above). For example, in a dual-lumen configuration, a mainlumen may be located in the axial center of the balloon shaft, and maybe configured to house a main guide wire. A secondary lumen may belocated along the side of the balloon shaft, and may be configured tohouse a secondary guide wire. The exit point for the secondary lumen maybe at the distal end of the balloon, and may occur where the balloontapers—i.e., at or near a “shoulder region” of the balloon. Thissecondary guide wire may maintain access to a side branch of abifurcated vessel during a stent deployment procedure. In someembodiments, three stents may be deployed, one in each branch of thebifurcation. The device may maintain a low profile to ensure that itfits in the entity being treated (e.g., a coronary vessel or other typeof vessel). The stent(s) may be chosen, for example, based on the sizeof the vessel and the length of the lesion.

In various embodiments, the stent may be positioned on the balloon sothat the stent is at the shoulder of the balloon, just as the balloontapers. As the inventor hereof has discovered, when the balloon isinflated for stent expansion, the portion of the balloon distal to thestent should immediately taper and the balloon should not push the stentback from its desired location within the vessel directly at the carina.In contrast, conventional stent delivery systems typically place thestent in the center or middle of the balloon, with a ˜0.5 to 1 mm ofballoon extending or “overhanging” proximal and distal to the stent. Thedistal portion of the balloon beyond the distal edge of the stent isgenerally larger than either side branch. During stent inflation, theends of the balloon that are not covered by the stent expand first.Since side branches are generally smaller than the main branch, whenthere is a size mismatch of the distal balloon with respect to the sizeof the side branch vessel, the distal balloon-end expansion in aconventional delivery system invariably displaces the stent away fromthe carina. Again, at least in part because certain of the techniquesdescribed herein allow accurate positioning of the stent at the carinaof the bifurcation, these techniques represent a significant improvementover conventional delivery systems. Conventionally, because of branchvessel overlap, it is difficult to identify the true bifurcation. Thebifurcation seen by angiography may not accurately correspond to thetrue anatomical bifurcation. This difficulty is overcome by thetechnique described herein, because the anatomical bifurcation isphysically identified. This not only guarantees that the stent is placedaccurately at the bifurcation, it also saves the patient from beingexposed to additional contrast and radiation.

A 0.014-inch guide wire or the like may be placed in each lumen orchannel of the balloon. The assembled device may be placed in the vesselusing the main guide wire. As the device moves along main guide wirethrough the vessel, the secondary guide wire may be guided into a sidebranch. The device may be advanced, for example, until it naturallystops at the carina of the bifurcation due to the secondary wirepositioned into the side branch. At this point, the operator may know orsense that the device is positioned accurately at the carina. Forexample, the secondary wire in the second side branch may be observed tobuckle slightly and a resistance to forward progress of the stent willbe felt physically by the operator. Additionally or alternatively,radiolucent markers or the like on the balloon shaft, stent, and/ordistal tip of the tube or channel under the stent may facilitatepositioning of the balloon during this procedure. Also, in some cases,the un-inflated stent may have a distal marker or may be more visiblebecause it is not inflated and/or because it is more radiolucent, as isthe case of platinum chromium stents (e.g., ION® or PROMUS® stents).

The balloon catheter may then be inflated and the stent deployed. Inthis manner, access to the side branch and main branch within the lumenof the stent may be maintained with the two guide wires. Next, a firstkissing balloon technique may be used to splay the stent to conform tothe bifurcation. The two balloons may be sized as per the approximatediameters of each side branch so as to splay the stent appropriatelywithout damaging the side branches. Once the kissing balloons have beeninflated, the stent in the main branch may be splayed across the carina.Thereafter, stents of the appropriate size may be deployed in a kissingmanner into the side branches of the bifurcations. These two stents maybe positioned so that the proximal part of the respective stents isexactly at the carina. A second kissing balloon technique may be used tofurther inflate the branch stents and the main vessel stent, and furthercause opposition of the stents into the intima of the vessel.High-pressure inflations may be used.

For sake of illustration, a typical procedure for kissing stentsdeployment may be conducted as follows. When one of the kissing balloonsis inflated to approximately ˜10-16 atm, the other balloon may beinflated to approximately ˜4 atm (and vice versa for the other stent).Thereafter, both balloons may be brought down to approximately ˜5-8 atmand deflated at the same time to ensure that the carina is correctlypositioned. It should be understood, however, that the inflationpressures to be used are dependent on the size of the vessel, thecompliance of the inflating balloons, manufacturer recommendations, etc.In the dual balloon stent configuration, for example, the two balloonsizes selected may be small enough to not damage the main vessel and yetcapable of pre-dilating the distal side branches to facilitate thekissing stents to follow.

In various applications, a stent delivery device may be used to deploystents designed to treat stenosis and/or other vessel conditions.Techniques for deploying these stents accurately at bifurcated lesionsare described below.

Turning now to FIG. 1, a diagram of a bifurcated vessel is depicted.Generally, the lengths and diameters of the various elements ofbifurcated vessel 100 may vary depending upon their location in apatient's body. As illustrated, bifurcated vessel 100 includes mainbranch 110, which splits between side branches 120A-B. Carina 130represents a region of bifurcated vessel 100 where side branches 120A-Bare joined together. In some cases, carina 130 may also be referred toas a “vertex” or “crotch point” of bifurcated vessel 100. Plaque 140 isillustrated along the surfaces or walls of bifurcated vessel 100 torepresent stenosis or other types of lesions.

FIG. 2A is a diagram of a dual-lumen balloon catheter according to someembodiments. In particular, balloon catheter 200A may include proximaltapered end 210 and distal tapered end 220. Catheter 200A may alsoinclude main or primary guide wire lumen (or channel) 230 as well asside or secondary guide wire lumen (or channel) 240. Main guide wirelumen 230 may include exit 250, and may be configured to receive a firstguide wire (i.e., a main or primary guide wire—not shown) through mainwire port 201. Conversely, side guide wire lumen 240 may include end260, and may be configured to receive another guide wire (i.e., a sideor secondary guide wire—not shown) through second wire port 202. Ballooninflation port 203 may be utilized deliver dilute contrast or anothersuitable fluid to lumen 280 or chamber 281 so as to inflate catheter200A during a delivery procedure. In some cases, lumen 280 or chamber281 may at least partially surround main guide wire lumen 230.

As illustrated in FIG. 2A, exit 250 of main lumen 230 through shaftportion 251 may be located at or near the center portion (i.e., theaxis) of catheter 200A, whereas end 260 of side lumen 240 may be locatedat or near (e.g., immediately after) proximal edge 270 of distalshoulder region 220 of catheter 200A. It may also be noted that catheter200A tapers between proximal edge 270 of distal shoulder region 220 (orend 260) and distal edge 271 of distal shoulder region 220, which iswhere the balloon joins shaft 251 in an approximately conical taperedfashion. Accordingly, proximal edge 270 of distal shoulder region 220may sometimes be referred to as a “tapered edge,” “tapered shoulder,” or“shoulder” of catheter 200A.

In some embodiments, proximal edge 270 may be defined as the point alongcatheter 200A where it begins to taper into region 220. And in somecases, end 260 may be located exactly at proximal edge 270. In othercases, end 260 may be located at a distance from proximal edge 270 sothat lumen 240 ends before edge 270 or extends beyond edge 270.

The individual guide wires may be placed through the main vessel andinto the two side branches of the bifurcation before the dual lumenstent balloon is loaded. In this case, the guide wires should not betwisted around each other, which would obstruct the movement of thestent balloon as it travels along the guide wires and through the mainvessel to the carina location. In some cases, the dual lumen catheter inthe configuration of FIGS. 2A-2E may aid in such parallel placement ofwires. In the configuration of FIG. 4C, for example, such parallelplacement of the guide wires may be achieved beforehand (e.g., the TwinPass Dual access Catheter model 5200 by Vascular Solutions Inc.).

FIGS. 2B-E illustrates alternative embodiments of a dual-lumen ballooncatheter. Particularly, FIG. 2B shows side guide wire lumen 241 with end261 located at distal edge 272 of proximal tapered portion 210 ofcatheter 200B. In some cases, the embodiment of FIG. 2B may be used, forexample to deliver a stent distal to the carina of a bifurcated vessel(as shown in FIGS. 4D and 4E).

FIG. 2C shows side guide wire lumen 242 with first exit 262 located ator near distal edge 272 of proximal tapered portion 210 (i.e., a “firsttapered edge”) and end 260 located at or near proximal edge 270 ofdistal tapered portion 220 (i.e., a “second tapered edge”) of catheter200C. As such, the embodiment of FIG. 2C is a “universal” ballooncatheter with the capability to accurately deliver a stent locatedproximal or distal to the carina.

FIG. 2D shows an alternative configuration of side guide wire lumen 243with end 263 located at proximal edge 270 of distal tapered portion 220,but running alongside main guide wire lumen 230 for a least a portion ofthe length of balloon catheter 200D.

FIG. 2E shows yet another alternative configuration of a universalballoon catheter 200E with two wire lumens; lumen 240 terminating atopening 260 at edge 270 and lumen 244 terminating at opening 264 at edge272.

Referring to FIG. 3, a cross-sectional view of balloon catheter 200A ofFIG. 2A is depicted. In this embodiment, lumen 230 is usually locatedapproximately at the center of catheter 200A, and lumen 240 is locatedoutside the perimeter of catheter 200A. In alternative embodiments,lumen 240 may also be located along the perimeter but within ballooncatheter 200A. Again, end 260 of lumen 240 may be located at or nearshoulder region 270 of catheter 200A, near a point where catheter 200begins to taper off (i.e., proximal edge 270 of distal shoulder region220).

In various embodiments, radius 300 of catheter 200A may be designed soas to determine an angle or degree of tapering of distal end 220 and tofacilitate insertion of catheter 200A in vessels of varying sizes. Forexample, a small radius 300 may reduce the profile of catheter 200A.Conversely, a large radius 300 may allow bifurcations with large anglesand/or diameters to be properly treated using catheter 200A. In a numberof applications, the distal balloon end may taper from the shoulderonwards as rapidly as technically feasible. Moreover, in some cases, aset of two or more catheters 200A with different diameters may beavailable, and a user or operator may select a suitable one among theset based on a location within the patient's body where a stentprocedure will be performed (e.g., coronary arteries may require lowprofile, etc.).

It should be noted that, except in FIGS. 6, 7, 16A-C and 17A (where thestent balloon diagram represents an unexpanded balloon with the stentcrimped on it), all other balloon diagrams (FIGS. 2A-E, 3, and 4A-G) areshown with the balloon expanded somewhat, but this is entirely forillustrative purposes. FIG. 4H is a self-expanding stent and does notrequire a balloon for deployment. Generally speaking, balloon lumen 281is collapsed when the stent is crimped on the balloon (i.e., the balloonis folded in an unexpanded state under the crimped stent). FIGS. 4E,8-11, 12A, and 17B may represent expanded versions of the stent-balloonconfiguration in some situations.

FIG. 4A is a diagram of bifurcation stent delivery device 400A accordingto some embodiments. As illustrated, device 400A utilizes the ballooncatheter 200A depicted in FIG. 2A. Specifically, stent 440 may bepositioned on the outer surface of balloon catheter 200A. In some cases,a distal edge of stent 440 may be aligned with edge 270 of shoulderregion 220 on catheter 200A. Main guide wire 410 may be positioned in avessel in a location desired by the operator or surgeon. Note that inmost instances, wire 410 may be placed in the vessel across the lesionin the main branch 110 (shown in FIG. 1) and further across the firstside branch 120-A (shown in FIG. 1), which is chosen because it is themore difficult lesion to cross. Wire 420 may be placed across the otherside branch 120B (shown in FIG. 1) beforehand or after the stentapproaches the carinal bifurcation point 130 (shown in FIG. 1).

Main guide wire 410 is inserted through main lumen 230 of catheter 200Ainto end 250 and out of proximal end 201 (shown in FIG. 2). Catheter200A is then advanced along guide wire 410 into the vessel andpositioned as desired. Similarly, side guide wire 420 may be insertedthrough side lumen 240 of catheter 200A into end 260 and out end 202(also shown in FIG. 2). In other embodiments, as shown in FIGS. 2B and2C, lumen 240 may terminate at the distal shoulder 272 of tapered region210, where side guide wire 420 may exit through end 261 or exit 262(shown in FIGS. 2B and 2C). Alternatively, the side guidewire 420 may beintroduced through the proximal end 202 into lumen 240 to exit from theend 260, 261 or 262 as the case may be, after the catheter 200A hasalready been advanced into the artery close to the carina.

FIG. 4B shows an alternative configuration for bifurcation stentdelivery device 400B according to some embodiments. Specifically, device400B employs balloon catheter 200D shown in FIG. 2D.

FIG. 4C shows stent delivery device 400C where the second side guidewire channel 244 is approximately the same length as the cylindricalportion of the balloon and slightly longer than the stent 440 spanningfrom shoulder 272 to shoulder 270. In this configuration, both wires 410and 420 may be placed across the main branch and side branches 120A and120B (shown in FIG. 1) before threading the guide wires into the stentdelivery device 400C. Wires 410 and 420 may be of approximately the samelengths allowing for one catheter to be exchanged for another.

FIG. 4D illustrates a bifurcation stent delivery device 400D usingballoon catheter 200B of FIG. 2B. In this embodiment, as previouslyshown, side guide wire 420 may leave side guide wire lumen 240 throughend 261. As such, this device configuration may be particularly wellsuited for accurately placing stent 440 at the carina beyond the mainbranch and into one of the side branches 120A or 120B (shown in FIG. 1).

FIG. 4E shows device 400D positioned within side branch 120A beyondcarina 130. As device 400D is insertion into side branch 120A, guidewire 420 causes device 400D to stop at carina 130 with stent 440accurately located at carina 130 and extending into branch 120A. In somecases, such a technique may be used, for example, to preserve sidebranches and/or to prevent jailing of the side branch—i.e., prevent thestent from deployed in such a way as to block or partially block accessto the side branch Besides accurate positioning of the stent beyond thecarina, the added advantage of this technique is that the wire 420maintains access to the side branch 120B in case side branch 120B needsintervention should the carina shift laterally and obstruct blood flowto the side branch 120B.

FIG. 4F shows bifurcation stent delivery device 400F employing ballooncatheter 200C of FIG. 2C. Particularly, balloon 200C may have two exitpoints (260 and 262) in lumen 242 for guide wire 420. For example, wire420 may leave catheter 200C through exit 260 (at or near edge 270 ofdistal tapered region 220) for placement of stent 440 at the carina of abifurcation and just before a side branch. Proximal exit point 262 (ator near edge 272 of proximal tapered region 210) may be used to placestent 440 accurately after the carina and within a side branch.

FIG. 4G shows device 400G with a balloon catheter with threelumens—center lumen 230 and side lumens 240 and 245. Each lumen isconfigured to hold a different guide wire 410, 420, 430. As such, device400G may be particularly well suited for a procedure involving atrifurcation or the like (e.g., where a vessel includes a main branchsplitting into three side branches). In this case, each of guide wires410, 420, 430 may facilitate positioning a stent with respect to each ofthree side branches.

FIG. 4H shows bifurcation delivery device 400H in a configurationsuitable for use with self-expanding stents. Particularly, device 400Hincludes outer sheath 450, self-expanding stent 440, and inner shaft460, as well as main lumen 230 and side channel 246. Delivery of stent440 may be accomplished by unsheathing stent 440, for example, bypulling back outer sheath 450. In the experience of the inventor hereof,the self-expanding stent should be oversized to the extent that it hasto splay and closely conform to the spread of the bifurcation. Often thestent has to be partially released a millimeter or two before the carinaand simultaneously gently advanced forward to get it to the carina andsometimes a fraction of the strut length beyond the carina. Thus, amethod of deploying a self-expanding stent may be different from anothermethod using a balloon expandable stent. Typically, self-expandingstents are intended for peripheral use. A bifurcation deployment may beconsidered, for example, the common Iliac bifurcation to the externaland internal Iliac or the common femoral to superficial femoral andprofound femoris bifurcation. The use of a second wire lumen 246, asdescribed herein, may allow accurate placement of the stent at thebifurcation while allowing for luminal placement of both of the wires ineach side branch vis-à-vis the stent in the main vessel.

FIG. 5 is a flowchart of a bifurcation stent delivery techniqueaccording to some embodiments. To further illustrate this technique,reference is also made to FIGS. 4A-G and 6-12. At block 505, a user oroperator may position a stent (e.g., stent 440 in FIG. 4A) with its edgeat or near a proximal edge (e.g., 270) of distal shoulder region (e.g.,220) of a balloon catheter (e.g., 200A). At block 510, the user mayinsert a first guide wire (e.g., main wire 410) in a first lumen,channel, or cavity (e.g., main lumen 230) of the catheter and/or mayalso insert a second guide wire (e.g., side wire 420) in a second lumen,channel, or cavity (e.g., side lumen 240) of the catheter. In othercases, however, a medical device manufacturer or the like may performthe operations indicated in blocks 505 and 510 to provide apre-assembled bifurcation stent delivery device as shown in FIGS. 4A-G.

At block 515, the user may place the bifurcation stent delivery devicein a patient's vessel using the first guide wire. For example, if themain guide wire is the “first guide wire,” it may be placed across themain vessel and into one of the branches. Typically, the first guidewire may be placed across the lesion in the main branch and the sidebranch that presents the more challenging stenosis to cross. Thisoperation is shown in FIG. 6, as device 400A is introduced into mainbranch 110 toward the bifurcation into branches 120A and 120B. Thesecond guide wire may be placed in the second branch (e.g. 120B)beforehand or as the stent approaches the bifurcation depending upon theconfiguration of the bifurcation stent delivery device. In some cases, aportion of side wire 420 leaving the device may be shaped at a firstacute angle alpha (α) designed to (at least approximately) match asecond acute angle beta (β) between side branches 120A and 120B, andtherefore be inserted into side branch 120B. FIG. 6 also shows main wire410 positioned inside one of the branches (e.g., branch 120A) ofbifurcation 100 (for ease of illustration, stenotic plaques are notdrawn). It will be understood that the main branch 110 and side branches120A and 120B as drawn in the figures are merely examples for thepurpose of illustration. The stents and methods described herein may beused with any sizes and any configuration of the main branch 110 andside branches 120A and 120B.

Returning to block 515, the user may advance device 400A until it stopsat the carina of the bifurcation. This is illustrated in FIG. 7, wheredevice 400A positions stent (e.g., 440) exactly at carina 130. Inparticular, FIG. 7 shows that side wire 420 may enter the other sidevessels (e.g., 120B), and thus cause the insertion of device 400A tonaturally stop at carina 130.

At block 520, the user may inflate the balloon catheter to deploy thestent while maintaining access to the first and second branches of thebifurcation via the first and second guide wires, respectively. FIG. 8shows catheter 200A after it has been inflated so that expanded stent440 is correctly positioned with respect to the bifurcation. FIG. 9shows stent 440 expanded at carina 130 and straddling it after thecatheter 200A has been deflated and removed. FIG. 9 also shows that sideguide wire 420 has been positioned deeper within side branch 120B afterdeflation of catheter 200A. This may be achieved by advancing wire 420into the side branch 120B simultaneously as the balloon deflates.Subsequently, the balloon catheter may be removed in a manner so thatboth guide wires (410 and 420) remain in place in each respective sidebranch. Importantly, it should be noted that both wires (410 and 420)are within the lumen of the stent.

At block 525, the user may apply a first kissing balloon procedure tosplay the deployed stent 440 and to cause it to more fully conform tothe walls of the bifurcation between the first and second side branches.FIG. 10 shows balloons 1000 and 1010, which have been advanced alongtheir respective guide wires 420 and 410 through expanded stent 440 andinto the side branches. The balloons 1000 and 1010 are inflated, therebycausing stent 440 to further expand and conform to the shape of thevessel at the bifurcation. After inflation of balloons 1000 and 1010,stent 440 is splayed across the bifurcation at carina 130. FIG. 11 is adiagram illustrating stent 440 fully splayed across carina 130 as aresult of the first kissing balloon procedure after the balloons havebeen deflated and removed.

Returning to FIG. 5, at block 530 the user may apply a second kissingballoon procedure to deploy a kissing stent within each branch of thebifurcation. The second kissing balloon procedure is illustrated inFIGS. 12A and 12B. FIG. 12A shows balloon 1201 with stent 1202 andballoon 1203 with stent 1204. Balloons 1201 and 1203 have been advancedalong the guide wires 410 and 420, respectively, through expanded stent440 and into the side branches. Balloon 1201 and first kissing stent1202 are positioned within first branch 120A and then balloon 1201 isinflated to expand stent 1202. Balloon 1203 and second kissing stent1204 are positioned within second branch 120B and then balloon 1203 isinflated to expand stent 1204.

FIG. 12B depicts the result of the second kissing balloon procedure withthe deploying devices 1201 and 1203 removed from the vessel. As shown inFIGS. 12A and 12B, there may be an area of overlap between or amongstents 440, 1202, and 1204 during inflation and after the balloons havebeen withdrawn. Unlike conventional or traditional bifurcation stentingmethods, the methods described herein may ensure that the deployedstents are positioned accurately at the carina and cover the entirebifurcation uniformly. Depending upon the type of stent used, this mayallow anti-restenosis drugs to be uniformly delivered to thebifurcation. Additionally, it is also to be noted that the methodsdescribed herein may ensure that all stent struts are opposed to thewalls of the bifurcation, thus minimizing or otherwise reducing thechance of stent thrombosis.

Therefore, using the techniques outlined above, stents 1202 and 1204 maybe positioned at the carina 130. These stents may be the regularpre-mounted stents, and in most cases may not need to be reconfigured inany way. The stents used in the second kissing procedure may be deployedat the same time or sequentially. The configuration shown in FIG. 4E maybe used to deploy stents 1202 and 1204 accurately at the carina 130 andbeyond. For example, a first stent delivery device may enter the vesselwith lumen 230 on the wire 410 and with side branch wire 420 goingthrough lumen 241. This would be used to deploy stent 1202. A secondstent delivery device may then enter the vessel with lumen 230 on wire420 and with side branch wire 410 going through lumen 241. This would beused to deploy stent 1204.

After stents 1202 and 1204 have been deployed, another kissing ballooninflation across the bifurcation (e.g. FIG. 10) may be employed tocomplete the procedure and cause optimal or otherwise improved expansionand opposition of the stents to the wall of the vessel. This particularstent deployment technique at the carina may save on the amount ofradiation and/or contrast usage, and it may improve patients' outcomesdue to its ability to position stents accurately at the carina.

Alternatives to Multi-Lumen Balloon Catheters

In some situations, a pre-configured or pre-manufactured dual-lumenballoon catheter may not be readily available to a user. However, one ormore of the stent deployment methods described herein may be used withsingle-lumen, conventional catheters. This is the second group or typeof devices referred to above. For example, a dual-guide wire stent maybe constructed from a single-lumen catheter stent by adding a secondguide wire between the stent and the balloon. The stent may be removedfrom the balloon and the second guide-wire positioned inside the stent.The stent may then be reinstalled on the balloon.

Starting with a single-lumen catheter, a stent delivery device may beassembled in different ways depending upon the type of stent being used(i.e., a closed-cell stent versus an open-cell stent). For example, theoperation of removing the stent from its balloon catheter may beperformed differently open-cell versus closed cell stents, so as tomaintain the integrity of the stent. Typically, open-cell stents cannotbe properly crimped back onto the balloon once expanded becausenon-linked struts tend to not fold back well. In contrast, a closed-cellcan usually be crimped back after being expanded. For example, ifMedtronic Inc.'s ENDEAVOR® or RESOLUTE INTEGRITY® open-cell stents areused, the stent may be taken off the balloon without inflating theballoon catheter. Alternatively, a closed-cell stent such as CordisCorporation's CYPHER® stent may be taken off the balloon by firstinflating the balloon and then expanding the stent.

The dual balloon and other configurations of open-celled stents asdescribed herein may be pre-manufactured. This would ensure that theopen cell stents are not damaged by manual handling of the stents.

This stent configuration (i.e., a balloon catheter, a stent, and asecond guide-wire positioned between the balloon and the stent) may beconstructed by the operator or may be pre-built by a manufacturer. Anadvantage of this configuration is that its cross-section profile may bethe lowest, especially if the device is pre-built by the manufacturer,due to the missing side lumen. However, the same configuration mayrequire above-average operator skill to maneuver the second wire trappedunder the stent into the side branch. Specifically, the entireballoon-stent-second-wire device may have to be maneuvered into the mainbranch and turned so that the second wire enters the second side branch.In some cases, to alleviate these concerns, a spring-coiled tip wire(e.g., Boston Scientific Corp.'s CHOICE® Floppy Guide Wire or theZinger® Support Guidewire by Medtronic) may be used as the second wireunder the stent and the tip may be steered into the second side branch,even though the spring coil is under the stent, because the distal wiretip is connected to the steel core of the wire under the spring coils.

Again, in the case of the off-label use of a closed-cell stent, forexample, a traditional stent balloon (e.g., the CYPHER® stent) may beinflated outside the body and the stent expanded. A secondary wire(e.g., a 0.014 spring tip wire because the internal stent wire isattached to the tip and can rotate the tip even if the wire is under thecrimped stent) may be introduced between the balloon and the stentstruts. The stent may be re-crimped to trap the secondary wire betweenthe stent and the balloon. In some applications, an approximately ˜3-5mm tip of the wire may be kept curved beyond the stent. Additionally, a0.014 guide wire may be introduced to the main (or only) lumen toprevent damage to this channel when re-crimping the stent. As describedabove, the stent may be positioned forward onto the distal shoulder ofthe balloon, usually at the distal edge of the distal balloon marker onthe shaft. The stent may be then re-crimped (e.g., manually by theoperator's fingers), and a #2.0 silk or the like may be wrapped aroundthe stent and further crimped manually. A 6F sheath may also be cut intoapproximately ˜1.5-2.5 inches, split, and placed on the shaft of theballoon with the second wire in it. The proximal side of this piece ofthe sheath may be beveled and used to introduce the stent through thevalve of a Touhy borst adapter or another medical apparatus used forattaching catheters to other devices. The stent may be loaded on thewire that is main branch of the bifurcation. As the stent is advanced,the secondary wire may be manipulated so that it enters the side branchof the bifurcation. Again, the stent may advance until it stopsnaturally at the carina. After the stent is deployed at the carina andthe balloon is being deflated, the side branch wire may be advanced intothe side branch, and the process may continue similarly as otherwisedescribed herein.

In the case of the off-label use of an open-cell stent, an operator mayreceive an assembled device including a balloon catheter and theopen-cell stent. As before, the balloon catheter may be a single-lumencatheter—i.e., configured to accept only one guide wire. However, ratherthan inflating the balloon to expand the stent, the operator may slidethe stent off of the balloon to remove it from the assembly. The stentmay be loosened off the balloon by rocking the proximal and distalportions of the balloon shaft within the stent in multiple directions.This expands the stent minimally to get it off the balloon. For example,in some cases an approximately ˜8-9 mm stent may be used for thispurpose. Then, a second guide wire may be added between an inner surfaceof the stent and an outer surface of the balloon catheter, and the stentmay be slid back over the catheter, thus trapping the second guide wirebetween the stent and the catheter. The distal edge of the stent in theassembled device may be at the distal shoulder region of the balloon.The stent may be re-crimped manually, for example, with a #2 silk threadsimilarly as described for the closed-cell stent above.

In some situations, when there is a stent with a second wire under thestent, either assembled at the time of the case with available materials(as described above) or pre-manufactured as described herein, anintroducer device may be used to get the stent-wire configuration acrossa hemostasis valve without damaging or changing the shape of the secondguide wire tip protruding from the distal edge of the stent. Such anintroducer may be manufactured in vitro, for example, by cutting anappropriate length of a #6 French sheath as described above.

FIG. 13A illustrates open-cell stent 1305 that may be used to assemble abifurcation delivery device following the operations described inconnection with FIG. 14. Particularly, open-cell stent 1305 with a crownof struts 1330 may have one or more struts unattached to the adjacentcrown of struts, thus creating a few struts 1310 that areinterconnected. In this case, cells 1340 are considered to beopen—although, typically, one of every 3-6 cells may be connected toeach other.

FIG. 13B shows closed-cell stent 1315, which may be used following theoperations described in FIG. 15. In contrast with open-cell stent 1305,every crown of struts 1335 of closed-cell stent 1315 is connected to theadjacent crown of struts 1335, thus creating all closed cells 1320.

FIG. 13C shows an example of a bifurcation stent delivery deviceemploying a single-lumen catheter, as described above. Device 1300 issimilar to device 400C shown in FIG. 4C, but without second lumen 244.In device 1300, side guide wire 1301 is crimped between stent 1302 andcatheter 1303. Although stent 1302 is illustrated as a closed-cell stent(e.g., as in FIG. 13B), an open-cell stent may also be used (e.g., as inFIG. 13A). In situations where the device is assembled by an operator inan “off-label” procedure (i.e., as opposed to pre-built by amanufacturer), the methods depicted in FIGS. 14 and 15 may be employed.Main guide wire 1304 is positioned in the vessel across the bifurcationand into a first branch. Device 1300 may be advanced along main guidewire 1304 into the vessel toward the bifurcation. Side guide wiresection 1301A will be guided into the second branch as device 1300approaches the bifurcation. Wire section 1301A may be curved to assistin “catching” the second branch. This will stop the balloon 1303 andstent 1302 adjacent to the carina of the bifurcation. The stent may thenbe deployed and splayed across the bifurcation as described above.

Turning now to FIG. 14, a flowchart of a bifurcation stent deliverydevice assembly using a single-lumen catheter with a closed-cell stent(e.g., in FIG. 13B) is depicted according to some embodiments. At block1405, the user may inflate the balloon to expand the stent outside thepatient's body. At block 1410, a user may position a stent at a forwardshoulder of a balloon catheter having a single lumen. Positioning thestent at the forward shoulder of the lumen will help to deploy the stentright at the carina of the bifurcation. At block 1415, the user mayinsert a secondary wire between the balloon and the stent. Then, atblock 1420, the user may re-crimp the stent to trap the secondary wirebetween the stent and the balloon while leaving a curved portion beyondthe stent. The curved portion will be directed into a side branch at thebifurcation to help position the stent at the carina.

The technique shown in FIG. 14 is particularly suitable for use withclosed-cell stents, where the stent is amenable to being expanded andre-crimped, thus returning to its original configuration. As theinventor hereof has recognized, in the case of open-cell stents, it maynot be possible to return the stent to its original form after itsinitial expansion. Nonetheless, it has been determined that, withrespect to pre-assembled stent delivery devices having an open-cellstent surrounding a balloon catheter, the open-cell stent in certaintypes of stents, may be removed from the assembly without causing damageto the stent or to the catheter without inflating the stent.

Accordingly, FIG. 15 is a flowchart of a bifurcation stent deliverydevice assembly using a single-lumen catheter with an open-cell stentaccording to some embodiments. At block 1505, the user or operator mayreceive the pre-assembled delivery device and may slide the open-cellstent off of the catheter to remove it from the assembly. In some cases,this operation may require that the user apply some amount ofmanipulation to loosen the stent and use some amount of gentle force toget the stent off the balloon. At block 1510, the operator may insert asecondary guide wire between the balloon and the stent. Then, at block1515, the user may slide the stent back over the balloon catheter, thustrapping the secondary guide wire between the stent and the balloonwhile positioning the distal edge of the stent at the tapered edge ofthe balloon, typically farther forward that its original position in theassembly.

In some cases, the pre-assembled device may be such that the edge of theopen-cell stent is positioned at the distal shoulder region of thecatheter (e.g., very close to, or exactly on the tapered edge). In manyapplications, such repositioning of the open-cell stent may ensure thatthe second guide wire, now trapped between the stent and the ballooncatheter, will cause a) the stent to stop at the carina of thebifurcation and b) the stent to be deployed accurately at the carina ofa bifurcation during balloon expansion.

FIGS. 16A-C are diagrams of alternative delivery devices according tosome embodiments. Particularly, FIG. 16A shows a dual balloonconfiguration 1600 with single stent 1601 crimped over two balloons 1602and 1603. Radiopaque markers on the shaft or the stent may be used tohelp position the stent at the carina. In some implementations, acommercially available stent-balloon catheter may be modified bycrimping stent 1601 over two parallel balloon catheters 1602 and 1603.Balloons 1602 and 1603 are sized to fit into the first and second sidebranches of a bifurcation. Two parallel guide wires 1605 and 1606 arefirst placed in the vessel and each guide wire is positioned into itsown side branch of the bifurcation. Each balloon 1602, 1603 is thenadvanced along the guide wires 1605 and 1606 though the vessel to thebifurcation. The two balloon-stent device 1600 may stop at the carinaand the stent then may be deployed at this location by inflating boththe balloons at the same time. In such an embodiment, the deployment andsplaying of the distal portion of the stent may occur at the same timeas pre-dilatation of the stenosis in the first and second side branches.If only open-cell stents are available on the market, this dual balloonconfiguration may be pre-manufactured. The configuration may be usedwith the closed-cell Cypher stent, but this stent is currently off themarket and no longer available from the manufacturer.

FIG. 16B depicts stent delivery device 1610 according to an alternativeembodiment. Specifically, stent 1611 is crimped over a parallelcombination of balloon catheter 1612 (for a first guide wire) and a longtube catheter 1613 with an approximately 0.014-inch wire lumen (for asecond guide wire). Device 1610 may also include markers (not shown) onthe shaft of the stent itself to assist in positioning the device. Theembodiment of device 1610 with catheter 1613 may facilitate accuratedelivery at the carina while maintaining dual side branch access throughthe stent lumen.

FIG. 16C depicts another embodiment of a stent delivery device. Stent1621 is crimped over balloon catheters 1622 and 1623. The catheters haveinflation balloon sections that are longer than stent 1621. As a result,sections 1625 on each balloon 1622, 1623 extend beyond the distal edgeof stent 1621. This configuration may be useful, for example, to dilateeach side branch 120A and 120B (FIG. 10) of the bifurcation when stent1621 is deployed. This would prepare the side branches for a subsequentkissing stenting operation. Additionally, the inflation of segments 1625in different side branches would cause stent 1621 to be splayed acrossthe bifurcation with the first inflation itself. This embodiment maymake it easier to splay stent 1621 in order to achieve the configurationdepicted in of FIG. 10 and FIG. 11, for example.

FIG. 17A illustrates a three-stent delivery device 1700 according toanother alternative embodiment. A stent 1704 is positioned on balloon1702 and stent 1705 is positioned on balloon 1703. Thereafter stent 1701is positioned around both the balloon catheters 1702 and 1703, with thedistal end of the stent overlapping the stents 1704 and 1705. Thisconfiguration allows for the simultaneous deployment of stent 1701 inthe main vessel before a bifurcation and deployment of stents 1704 and1705 in separate side branches.

FIG. 17B illustrates device 1700 deployed at a bifurcation. First, guidewires 1706, 1707 are positioned though main vessel 110 and into separateside branches 120A, 120B. Then, device 1700 is advanced along the guidewires with balloon catheter 1702 traveling along guide wire 1706 andballoon catheter 1703 traveling along guide wire 1707. As device 1700approaches the bifurcation, the balloons are directed into separate sidebranches. The device will stop moving into the vessel when the balloonsegments covered by stents 1704 and 1705 have entered the side branches.Stent 1701 cannot move into the side branches, but will be stopped atcarina 130. Once the device 1700 is positioned with stent 1701 at thecarina in this manner, the balloons 1702, 1703 may be inflated asillustrated in FIG. 17B. This inflation will simultaneously deploy stent1701 in the main vessel proximal to carina 130 and stents 1704, 1705 inthe side branches distal to carina 130. Additionally, device 1700performs the kissing balloon techniques when it is inflated, whichsplays stent 1701 across the bifurcation.

As a person of ordinary skill in the art will recognize in light of thisdisclosure, one or more of the numerous embodiments described herein mayprovide one or more advantages over known stent deployment techniques.For example, some of these embodiments may prevent guide wires frombecoming tangled. In some cases, access to a side branch may bemaintained using the second guide wire when deploying a stent in themain vessel. Furthermore, the wire going into the side branches may bemaintained within the lumen of the stent, rather than through the stentstruts. One or more of the techniques disclosed herein may alsoguarantee the exact location of the stent at the carina, which makes itless likely that areas of the bifurcation lesion will remain uncoveredby stents after treatment.

Moreover, in contrast with existing devices currently used to treatbifurcation lesions, one or more of the devices disclosed herein may bemanufactured with a low or small profile, may be easy to maneuver, andmay therefore be particularly well suited for the treatment of coronaryarteries, which are typically small in diameter (although it may also beused in any bifurcation lesion). In some devices, the side lumen mayensure access to the side branch of the bifurcation. Further, in somecases, the side guide wire may help place the main stent exactly at thecarina. Because in embodiments where the bare wire is trapped under thestent the side guide wire is generally unable to move within the lumen,a ‘V’ shape may be created between the guide wire and the ballooncatheter of the main branch stent. As the device advances with the sidewire in the side branch and the main wire in the main branch, it maystop at the vertex of bifurcation. As such, one or more of thetechniques described herein may guarantee precise placement of a stentat the carina with any amount of plaque buildup in the arteries, andwhile ensuring there is full coverage of the bifurcation. Underfluoroscopy in two dimensions, it is often very difficult to identifythe precise location of the carina in two dimensions because of variableside branch vessel overlap. Hence the particular suitability of certainof these techniques and innovations to accurately place stents atbifurcations in coronary, peripheral vascular, venous or otheranatomical locations.

In some cases, the stent delivery systems and methods described hereinmay provide a 100% or near 100% apposition or coverage of thebifurcation lesion by the stent struts, thereby eliminating a limitationof present day stenting of such lesions. In a typical scenario, 100%coverage of the lesion may be a particularly critical issue with locallesion drug delivery by drug eluting stents to prevent restenosis. Inaddition, 100% or near 100% stent apposition to the bifurcation lesionensures that luminal access to each branch is wide open—that is, stentstruts do not protrude into the lumen and a true pantaloonsconfiguration may be obtained. This method of stenting may thereforeeliminate or otherwise reduce the risk of stent thrombosis due to stentstruts that are not opposed to the wall of the vessel. Furthermore, inthe case of restenosis or new lesions developing downstream to thebifurcation, normal anatomical access allows subsequent operators tocross through the bifurcation with wires, balloons and stents withoutany metallic luminal obstacles caused by struts not in apposition to thewalls of the bifurcation.

In some cases, the stent delivery systems and methods described hereinmay also prevent the carina of the bifurcation from being shifted fromits anatomical location. This may be guaranteed by deflating the kissingballoons together at the same inflation pressures. The stent in the mainvessel may be accurately delivered at the carina by making sure that thedistal end of the stent is positioned forward on the shoulder or distaltaper of the deploying balloon than is the case with more conventionalstents. In addition, problems of plaque shifting are also eliminated orotherwise reduced. In various implementations, the two wires in eachlumen may always be within the lumen of the stents and do not at anytime go through stent struts.

Certain conventional balloon and stent profiles are small enough toutilize certain of the stent delivery techniques described herein, forinstance, through an 8F (crossing profile of the guiding catheter)system. For example, the closed-cell design of the CYPHER® stent isparticularly suitable for this method because it can be re-crimped afterexpanding it outside the patient's body. Other open cell stents such as,for example, the ENDEAVOR®, or the RESOLUTE INTEGRITY® may be loosenedand removed from the balloon without expanding the stent. Alsoconventional stents, wires, and materials may be used to reconfigure astent for delivery at the bifurcation (i.e., off-FDA label utilizationof these stents). While such an off-label technique may require a higherlevel of operator expertise for reconfiguration of the stent for thebifurcation, after the initial learning curve is overcome, such a methodis also very feasible.

With one or more of the innovations described herein, stent deliverysystems can be created to make the delivery operator friendly andachieve routine use for bifurcation stenting. Additional innovationsdescribed herein may be used to accurately deliver a stent at atrifurcation, for example, a left-main trifurcation into the leftanterior descending, ramus intermedius and circumflex arteries. Yetadditional innovations may accurately deliver stents beyond the carinawithout jailing a side branch. This may be utilized in othernon-bifurcation lesion situations where stenting is required in the mainvessel but the stent needs to be delivered without jailing a sidebranch, while maintaining access to the branch in case the carina isshifted.

As such, in various embodiments, the stent delivery systems and methodsdescribed herein may be particularly useful for use with patients whocannot undergo bypass surgery safely. Moreover, one or more of thesetechniques may be safely used in patients with “complex” bifurcationlesions, thus making complex bifurcation operations a matter of routine;thus helping decrease the need for such surgery.

The various systems and methods illustrated in the figures and describedherein represent example embodiments of systems and methods fordeploying stents within bifurcated blood vessels. The order in whicheach operation of a given method is performed may be changed, andvarious elements of the systems or devices illustrated herein may beadded, reordered, combined, omitted, modified, etc. Variousmodifications and changes may be made as would be clear to a person ofordinary skill in the art having the benefit of this specification. Itis intended that the invention(s) described herein embrace all suchmodifications and changes and, accordingly, the above description shouldbe regarded in an illustrative rather than a restrictive sense.

1. A device, comprising: a balloon catheter including a first lumen anda second lumen, the first lumen configured to receive a first guide wireand the second lumen configured to receive a second guide wire, thefirst lumen having a first exit at a center of a distal end of theballoon catheter, and the second lumen having a second exit at aproximal edge of a distal tapered portion of the balloon catheter,wherein the proximal edge is at a point of transition between acylindrical portion and a tapered portion of the balloon catheter. 2.The device of claim 1, wherein, upon being inflated, at least one of theproximal or distal tapered portions of the balloon catheter assumes aconical shape.
 3. The device of claim 2, further comprising: a stentsurrounding the balloon catheter, a distal edge of the stent alignedwith the proximal edge of the distal tapered portion of the ballooncatheter, for deployment of the stent proximal to the carina with thedistal edge of the stent exactly at the carina, and the proximal edge ofthe stent located at the distal edge of a proximal tapered portion ofthe balloon catheter, for deployment of the stent distal to the carinawith the proximal edge of the stent exactly at the carina.
 4. A device,comprising: a first balloon catheter; a stent positioned around thefirst balloon catheter; a first lumen in the first balloon catheter andconfigured to house a first guide wire; and a second lumen configured tohouse a second guide wire.
 5. The device of claim 4, wherein the openingfor the second lumen is positioned to prevent the second guide wire frompassing through struts of the stent.
 6. The device of claim 4, whereinwhen the first guide wire is positioned in a first vessel and the secondguide wire is positioned in a second vessel such that the first andsecond vessel form a carina, the opening for the second lumen positionedso that the device may be advanced along the first guide toward thecarina until the second guide wire prevents further advancement beyond apoint where a distal edge of the stent is adjacent to the carina.
 7. Thedevice of claim 4, wherein the second lumen is positioned between aninner surface of the stent and an outer surface of the first ballooncatheter.
 8. The device of claim 4, further comprising: a first openingin the second lumen, the first opening positioned at a proximal edge ofthe stent.
 9. The device of claim 4, further comprising: a first openingin the second lumen, the first opening positioned at a proximal edge ofthe stent; and a second opening in the second lumen, the second openingpositioned at a distal edge of the stent.
 10. The device of claim 4,wherein the second lumen is positioned within an outer surface of thefirst balloon catheter, the second lumen having an opening positioned ata distal edge of the stent.
 11. The device of claim 4, furthercomprising: an opening in the second lumen, the opening positioned at adistal edge of the stent; and a third lumen having an opening positionedat a proximal edge of the stent.
 12. The device of claim 4, furthercomprising: an opening in the second lumen, the opening positioned at adistal edge of the stent; and a third lumen having an opening positionedat the distal edge of the stent.
 13. The device of claim 4, wherein thesecond lumen is separate from the first balloon catheter and ispositioned between an inner surface of the stent and an outer surface ofthe first balloon catheter, the second lumen having an openingpositioned forward of a distal tapered region of the first ballooncatheter relative to the stent.
 14. The device of claim 4, furthercomprising: a second balloon catheter, wherein the second lumen ispositioned in the second balloon catheter and wherein the stent ispositioned around both the first and second balloon catheters.
 15. Thedevice of claim 14, further comprising: a second stent positioned aroundthe first balloon catheter; and a third stent positioned around thesecond balloon catheter.
 16. A device, comprising: an inner shaft; aself-expanding stent positioned around the inner shaft; an outer sheathpositioned around the self-expanding stent and configured to prevent theself-expanding stent from expanding; a first lumen formed in the innershaft and configured to house a first guide wire; and a second lumenformed in the inner shaft and configured to house a second guide wire,the second lumen having an opening adjacent to a leading edge of theself-expanding stent.
 17. The device of claim 16, wherein the main lumenis located in the axial center of the inner shaft.
 18. The device ofclaim 16, wherein the opening for the second lumen is positioned toprevent the second guide wire from passing through struts of theself-expanding stent.
 19. The device of claim 16, wherein when the firstguide wire is positioned in a first vessel and the second guide wire ispositioned in a second vessel such that the first and second vessel forma carina, the opening for the second lumen positioned so that the devicemay be advanced along the first guide toward the carina until the secondguide wire prevents further advancement beyond a point where the distaledge of the self-expanding stent is adjacent to the carina.
 20. Thedevice of claim 16, wherein the self-expanding stent is configured toexpand when the outer sheath is removed.